PubMed Health⌕ Search

Biomedical subjects

N Ohshita

Publications and source records attributed to N Ohshita.

11 recordsLinked to original sources
PubMed2005

Elimination of neurokinin-1 receptor neurons in caudal nucleus reverses the effects of systemic bicuculline on c-Fos expression in rat trigeminal sensory nucleus: I. High intensity electrical stimulation of the trigeminal ganglion.

Although neurokinin-1 receptor (NK-1)-bearing neurons are distributed in lamina I of the trigeminal caudal nucleus (Vc) and constitute major projection neurons, little is known about their fundamental role(s) in nociceptive processing. This study examines the effect of intra cisterna magna injection of substance P (SP) conjugated to saporin (SP-Sap; 5 microM, 5 microl) [with/without systemic administration of bicuculline] on c-Fos expression in the trigeminal sensory nucleus (TSN) induced 2 h after 10 min repetitive electrical stimulation of the trigeminal ganglion (TG) at high intensity (1.0 mA, 5 Hz, 5 ms) in the urethane-anesthetized rat. In the SP-Sap-treated rats, the numbers of NK-1-immunopositive neurons in laminae I and III of the Vc decreased compared with rats similarly pretreated with saline (Sal; 5 microl) or blank-saporin (Bl-Sap; 5 microM, 5 microl). In Sal- or Bl-Sap-treated controls, high intensity stimulation induced c-Fos expression in neurons throughout the full extent of ipsilateral superficial layers of the Vc (VcI/II), magnocellular zone of the Vc (VcIII/IV) and the dorsal or dorsomedial subdivisions of the rostral TSN above the obex (trigeminal principal, oral (Vo) and interpolar nuclei). Preadministration of bicuculline (2 mg/kg, i.p.) decreased the numbers of c-Fos-immunopositive neurons in the VcI/II, VcIII/IV and Vo in Sal- or Bl-Sap-treated controls. In contrast, high intensity stimulation induced less c-Fos-immunopositive neurons in the VcI/II and Vo of rats treated with SP-Sap compared with those in Sal- or Bl-Sap-treated controls. In SP-Sap-treated rats preadministered with bicuculline, the numbers of c-Fos-immunopositive neurons in the VcI/II and Vo were increased compared with the SP-Sap-treated rats preadministered with Sal. These results suggest that NK-1-immunopositive neurons in laminae I and III of Vc play a pivotal role in the nociceptive specific processing in the TSN through GABA(A) receptors.

Animals↗
PubMed2001

Detection of craniospinal dissemination of intracranial germ cell tumours based on serum and cerebrospinal fluid levels of tumour markers.

Nineteen intracranial germ cell tumours treated during the past 11 years were evaluated retrospectively. The tumours were classified into three groups according to the level of alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (HCG) in serum and cerebrospinal fluid, and the optimal treatment for each group was determined. Group A consisted of patients with normal titres of AFP and HCG, group B of patients with relatively high titres (< 10 times normal), and group C comprised patients with higher titres ( 10 times normal levels). In group A, an appropriate field and dose of irradiation was necessary to prevent craniospinal dissemination. In group B, none of four patients who underwent total or subtotal resection of the tumour had craniospinal disseminatio n or tumour recurrence, whereas dissemination occurred in four further patients, including two who had received radiochemotherapy only, and two who had undergone partial resection of the tumour. While patients in group C had dissemination at the time of initial diagnosis, most patients in group B developed dissemination more than 10 months after initial treatment, suggesting that the type of treatment received as first line therapy is important in patients in this group. The prognosis of patients in group C, however, was unaffected by the priority given to either surgery, radiation or chemotherapy as first line treatment. Craniospinal dissemination can be prevented in patients with germ cell tumours who have a relative increase in levels of AFP and HCG by aggressive removal of the tumours as first line therapy, regardless of the type of adjuvant therapy given.

Adolescent↗
PubMed2000

Postoperative changes in paraspinal muscle thickness after various lumbar back surgery procedures.

Damage to the paraspinal muscle after various lumbar back surgery procedures was evaluated by measuring the paraspinal muscle thickness preoperatively and postoperatively in 89 patients, 61 males and 28 females. There were 42 single interlaminar level procedures (SL group), 13 multiple interlaminar level procedures (ML group), and 34 posterolateral fusion procedures (PLF group). Changes in paraspinal muscle thickness were evaluated at more than 10 months after surgery, because muscle swelling continued as long as 10 months after surgery, and then reduced as the edema subsided. Postoperative serum creatine phosphokinase (CPK) level on postoperative day 2 was also measured. The decrease of paraspinal muscle thickness was significantly larger in the PLF group than in the SL group (-12.9% and -2.7%, respectively, p < 0.02). There was no significant correlation between postoperative serum CPK level and decrease of paraspinal muscle thickness. However, the postoperative elevation of serum CPK level was significantly higher in the PLF group than in the SL and ML groups (979 +/- 114 vs. 292 +/- 45 and 410 +/- 44 IU/l, respectively, p < 0.001). In conclusion, posterolateral fusion is the most invasive procedure of the paraspinal muscles in various lumbar back surgery procedures. Paraspinal muscle damage during lumbar back surgery may be one of the most important factors that causes atrophy of the muscles.

Adult↗
PubMed1999

Dorsally sequestrated thoracic disc herniation--case report.

A 53-year-old male presented with a rare dorsally sequestrated thoracic disc herniation manifesting as acute low back pain and weakness. He had no history of trauma. Magnetic resonance (MR) imaging demonstrated a mass at T10-11 intervertebral level connected with the T-10 disc. Axial MR imaging showed the mass had surrounded and compressed the dural sac from the lateral and dorsal sites. MR imaging with gadolinium-diethylenetriaminepenta-acetic acid showed slight rim enhancement of the lesion. Computed tomography detected no abnormal calcification. The diagnosis was thoracic disc herniation. Laminectomy resulted in rapid and satisfactory recovery. The histological diagnosis was thoracic disc herniation. MR imaging was very effective for the diagnosis based on the connection between the mass and the disc space. The differential diagnosis includes metastatic epidural tumor, epidural hematoma, and epidural abscess.

Acute Disease↗
PubMed1995

Effect of hyperthermia on cyclin B expression in a human glioblastoma cell line.

Effects of hyperthermia on the cell kinetics of glioblastoma cells were investigated using flow cytometry. Pulse-labeling with 5-bromodeoxyuridine (BUdR) and chasing of the labeled cells revealed temporary accumulation of the labeled cells in G2M phase and a reduction of DNA synthesis. The level of cyclin B rises rapidly in G2 phase and falls at the end of mitosis in normal cycling cells. Cyclin B binds to p34cdc2, resulting in histone kinase activity which is necessary for the initiation of mitosis. The amount of p34cdc2 remains constant throughout the cell cycle. The level of cyclin B was measured using an anti-cyclin B antibody and flow cytometry in order to investigate the cause of the G2 accumulation induced by hyperthermia. A low level of cyclin B, in comparison with that of normal cycling cells, persisted for more than 3 h after hyperthermia. These results indicate that the temporary accumulation of cells in G2M phase after hyperthermia may be caused, at least in part, by an insufficient level of cyclin B.

Antibodies, Monoclonal↗
PubMed1994

Prognostic implications of meningiomas in the elderly (over 70 years old) in the era of magnetic resonance imaging.

During the 5 years from 1987 to 1991, 89 elderly patients, aged 70 years and over, were admitted to departments of neurosurgery in Yamaguchi prefecture with meningioma. The clinical features and prognostic implications of meningioma in the elderly were assessed retrospectively. Seventy-eight (88%) of the 89 patients underwent surgery, which was a higher rate than has been previously reported. The length of clinical history was also shorter than in previous studies, and was partly due to the recent introduction of magnetic resonance imaging (MRI). The incidence of poor prognosis (severe disability, vegetative or dead) in the elderly and a younger group aged less than 70 years was 13% and 7%, respectively, but the difference was not statistically significant. In the surgically treated elderly group, age did not influence the patient's outcome. The factors affecting the outcome were pre-operative neurological deficit (p < 0.05), histological malignancy (p < 0.05), and multiple operations (p < 0.05). Twenty-seven of the elderly meningioma patients were in good physical condition with minimal neurological involvement. They underwent total removal of the tumour at the first operation, and the histological diagnosis was benign. Twenty-five of these 27 patients fell into the best outcome category. Therefore, age alone was not a factor preventing proper surgical treatment of meningioma in the elderly.

Aged↗
PubMed1993

Clinical evaluation of DNA index in human brain tumors.

We evaluated the DNA index values in 28 brain-tumor patients showing DNA aneuploidy on the DNA histogram obtained by flow cytometry. In 17 cases among them, the DNA index values were compared to BUdR labeling indices (BUdR-LI). Average DNA indices of individual tumor types were 1.89 +/- 0.10 (6 glioblastomas multiforme), 1.93 +/- 0.05 (4 anaplastic astrocytomas), 1.68 +/- 0.09 (3 malignant meningiomas), 1.24 +/- 0.03 (7 meningiomas), 1.19 +/- 0.05 (2 pituitary adenomas) and 1.86 +/- 0.24 (6 metastatic brain tumors). Slow-growing tumors such as meningioma and pituitary adenoma, had lower values than malignant tumors, except a case of a metastatic brain tumor. All malignant meningiomas had higher DNA index values than the other meningiomas. No difference was observed between the DNA index values of glioblastomas multiforme and anaplastic astrocytomas. DNA index values were correlated with BUdR-LI values (p < 0.05), and seven cases with low DNA index values (1.13-1.31) had low BUdR-LI values of less than 1%. Others with high DNA index values of 1.44 or more had high BUdR-LI values of 3.5% or more. These results suggest that high DNA index values is related to tumor malignancy, and despite the presence of some disparities, many slow-growing brain tumor has low DNA index values.

Adult↗
PubMed1990

Correlation of in vitro bromodeoxyuridine labeling index and DNA aneuploidy with survival or recurrence in brain-tumor patients.

There are no previous reports correlating the in vitro bromodeoxyuridine (BUdR) labeling index (LI) with the clinical outcome in patients with brain tumors. The reliability of the LI as a predictor of patient survival or recurrence was examined in this study of 66 human brain tumors (19 gliomas, 18 meningiomas, and 29 others). Anti-BUdR staining was performed on surgically extirpated tumor tissue that had been treated with BUdR as previously described. Correlation of the BUdR LI with patient survival or tumor recurrence rate was carried out by the method of Kaplan and Meier. Deoxyribonucleic acid (DNA) aneuploidy was estimated in 52 cases. The results of this study indicate that BUdR LI values correlated well with the clinical course of patients with brain tumor. In comparison with patients with higher LI's, there was both a significantly higher survival rate for tumors other than meningiomas and a higher recurrence-free rate for meningiomas in patients with LI's of less than 4% and 1%, respectively. Although there was a tendency for patients without tumor aneuploidy to show better survival data than the others, no statistical difference was observed. These results suggest that the in vitro BUdR labeling method is reliable for prediction of a patient's prognosis, whereas prognosis on the basis of DNA aneuploidy alone is uncertain.

Adolescent↗
PubMedDate not supplied

IFN-beta inhibition of etoposide resistance acquisition in vitro: studies using a human glioblastoma cell line.

The inhibition by IFN-beta of acquired resistance to the epipodophillotoxin etoposide was studied using a human glioblastoma cell line, T98G. T98G cells were exposed to either etoposide alone or both etoposide and IFN-beta, and after subculture, the same two series of drug exposure were repeated. Degree of level of resistance was tested by the response of the cells to etoposide and changes in their DNA histograms. Furthermore, topoisomerase II in each set of cells was subjected to fluorescence staining with monoclonal anti-topoisomerase II antibody, and the amount of fluorescence was measured by flow cytometry. Secondary etoposide exposure showed less cytotoxicity when the first exposure was to etoposide alone. In contrast, the cytotoxicity was almost the same as that after the first exposure when IFN-beta was added. Resistance to etoposide may result from qualitative or quantitative alterations in the target enzyme, topoisomerase II. The present results show that resistant cells have less topoisomerase II than sensitive cells, suggesting that IFN-beta inhibits the acquisition of resistance to etoposide by suppressing the alteration in topoisomerase II. The inhibition of acquired resistance to etoposide by IFN-beta suggests that continuous and repeated chemotherapy for glioblastoma and other malignant tumors may be clinically advantageous.

Antibodies, Monoclonal↗
PubMedDate not supplied

Measurement of labeling index of DNA polymerase alpha in human brain tumors. Comparative study with labeling indices of BUdR in vitro and Ki-67.

Proliferative activity of 28 human brain tumors was estimated by simultaneous measurement of DNA polymerase alpha, Ki-67 and bromodeoxyuridine (BUdR) labeling indices on microscopic tissue preparations stained immunologically with monoclonal antibodies using a peroxidase technique. All the antigens were exclusively found in the nucleus. The labeling index of BUdR was lower than those of the other indicators. The values of the DNA polymerase alpha labeling index were almost the same as those of the Ki-67 labeling index. Simultaneous measurement of these parameters may provide more useful information on tumor cell growth kinetics than that of a single parameter.

Adolescent↗